anetPeerToString(): make unix sockets distinguishable.
anetPeerToString(): make unix sockets distinguishable.

Following the CLIENT LIST output format, we prefix the unix socket
address with a "/" so that it is different than an IPv4/6 address.
This makes parsing simpler.

Related to #2010.

modulexcite/redis,itugs/redis,jasonkying/redis,MOON-CLJ/redis,vincent-vivian-liu/redis,csuhawk/redis,ctripcorp/redis,MOON-CLJ/redis,narma/redis,RepmujNetsik/redis,wprice/redis,AplayER/redis,dreamquster/redis,rogerlz/redis,ErikDubbelboer/redis,mcanthony/redis,h0x91b/redis,arijitvt/redis,jackyan/redis,gilala/bjredis,dreamquster/redis,shreesundara/redis,abhiklodh/redis,harrisonfeng/redis,PradheepShrinivasan/redis,francischan714/redis,yuhc/redis-benchmark-enhanced,AplayER/redis,4396/redis,universsky/redis,seandsky/redis,qiyang0221/redis,j0hnma/hszredis,wbailey5/redis,duanx/redis,wbailey5/redis,Soledad89/redis,antirez/redis,oranagra/redis,neomantra/redis,tellapart/redis,ytjiang/redis,j0hnma/hszredis,zczhuohuo/redis,ouyangkongtong/redis,xlzhan/redis,colstrom/redis,soloestoy/redis,nuxeh/redis,YongMan/redis,SummonY/redis,netroby/redis,riyan8250/redis,taoguan/redis,allengaller/redis,YuanZhewei/redis,valdsJohn/redis,netroby/redis,mingyaaaa/redis,honestme/redis,zguangyu/redis,elkingtonmcb/redis,GitHubMota/redis,OmarQunsul/graph-redis,a-pavlov/redis,timothyohare/3rdPartySrc-redis,nnog/redis,fengshao0907/redis,ituncle/redis,aim-for-better/redis,linfangrong/redis,GitHubMota/redis,hawkchch/redis,flashbuckets/redis,xujunhai1991/redis,july2993/redis,ofirluzon/redis,RepmujNetsik/redis,mgk/redis,z-fork/redis,alenslan/redis,tellapart/redis,mgk/redis,pmem/redis,AALEKH/redis,linfangrong/redis,PradheepShrinivasan/redis,tanghaodong25/redis,wenxueliu/redis_comment,jingjidejuren/redis,josiahcarlson/redis,SummonY/redis,clamoriniere1A/redis,MasahikoSawada/redis,soloestoy/redis,seppo0010/redis,izhoujie/redis,devaos/redis,Markgorden/redis,Wangyao14cyy/redis,JoeWoo/redis,gilala/hbjredis,clamoriniere1A/redis,hornen/redis,valdsJohn/redis,nuxeh/redis,StevenTsai/redis,programmecat/redis,PKRoma/redis,badboy/redis,universsky/redis,j0hnma/hszredis,janekmi/redis,cnbin/redis,neomantra/redis,xuguruogu/redis,davidradunz/redis,a-pavlov/redis,AplayER/redis,SyntaxStacks/redis,timothyohare/3rdPartySrc-redis,gaoxianglong/redis,antirez/redis,ErikDubbelboer/redis,tjschuck/redis,universsky/redis,ouyangkongtong/redis,cnbin/redis,weizijun/redis,YuraLukashik/redis,ton31337/redis,ituncle/redis,atreeyang/redis,wujf/redis,JoeWoo/redis,riyan8250/redis,pcarrier/redis,aim-for-better/redis,weizijun/redis,takeshineshiro/redis,ctripcorp/redis,riyan8250/redis,roth1002/redis,holstvoogd/redis,charsyam/redis,Aaron1992/redis,cloudrain21/redis,csuhawk/redis,harrisonfeng/redis,duanx/redis,j0hnma/szredis,flashbuckets/redis,mumingv/redis,mingyaaaa/redis,wangyikai/redis,jingjidejuren/redis,itugs/redis,h0x91b/redis,ouyangkongtong/redis,zhiliaoniu/redis,charsyam/redis,AALEKH/redis,fengshao0907/redis,ofirluzon/redis,modulexcite/redis,z-fork/redis,jackyan/redis,xujunhai1991/redis,SyntaxStacks/redis,alenslan/redis,PKRoma/redis,taoguan/redis,josiahcarlson/redis,rogerchina/redis,citusdata/redis,Aliceljm1/redis,StevenTsai/redis,supasate/redis,ytjiang/redis,qiyang0221/redis,Soledad89/redis,spinlock/redis,arijitvt/redis,mengyou0304/redis,citusdata/redis,wprice/redis,190235047/redis,arijitvt/redis,OmarQunsul/graph-redis,atreeyang/redis,allengaller/redis,izhoujie/redis,rogerlz/redis,Sciumo/redis,kmiku7/redis,pcarrier/redis,mingyaaaa/redis,zczhuohuo/redis,LongXQ/redis,mengyou0304/redis,SummonY/redis,zguangyu/redis,dayuoba/redis,YongMan/redis,supasate/redis,ofirluzon/redis,honestme/redis,itugs/redis,SummonY/redis,YongMan/redis,LongXQ/redis,sunheehnus/redis,nnog/redis,spinlock/redis,PKRoma/redis,saisai/redis,badboy/redis,CodeJuan/redis,kaushik94/redis,sunheehnus/redis,YuraLukashik/redis,wangyikai/redis,a-pavlov/redis,rouzier/redis,tellapart/redis,hedisdb/hedis,july2993/redis,ncopa/redis,ctripcorp/redis,aim-for-better/redis,pkdevbox/redis,PKRoma/redis,davidradunz/redis,charsyam/redis,dayuoba/redis,ErikDubbelboer/redis,seppo0010/rlite-server,mumingv/redis,yuhc/redis-benchmark-enhanced,universsky/redis,blackmady/redis,itamarhaber/redis,4396/redis,brg-liuwei/redis,z-fork/redis,devaos/redis,jingjidejuren/redis,gilala/hbjredis,gilala/bjredis,JoeWoo/redis,brg-liuwei/redis,saisai/redis,shreesundara/redis,narma/redis,Markgorden/redis,ncopa/redis,takeshineshiro/redis,hornen/redis,supasate/redis,Aliceljm1/redis,kensou97/redis,seppo0010/rlite-server,blackmady/redis,190235047/redis,vincent-vivian-liu/redis,Soledad89/redis,YuraLukashik/redis,z-fork/redis,honestme/redis,citusdata/redis,alenslan/redis,duanx/redis,hornen/redis,seppo0010/redis,ncopa/redis,taoguan/redis,RepmujNetsik/redis,YuanZhewei/redis,wprice/redis,shreesundara/redis,thomasdarimont/redis,shining-yang/redis,AplayER/redis,cnbin/redis,hgl888/redis,kensou97/redis,AALEKH/redis,mattsta/redis,josiahcarlson/redis,MasahikoSawada/redis,thomasdarimont/redis,sunheehnus/redis,elkingtonmcb/redis,nnog/redis,seandsky/redis,rogerchina/redis,csuhawk/redis,twskipper/redis,charsyam/redis,neomantra/redis,neomantra/redis,mengyou0304/redis,colstrom/redis,wenxueliu/redis_comment,MOON-CLJ/redis,Sciumo/redis,weizijun/redis,mengyou0304/redis,mgk/redis,rouzier/redis,pcarrier/redis,pkdevbox/redis,oranagra/redis,wenxueliu/redis_comment,mcanthony/redis,timothyohare/3rdPartySrc-redis,wbailey5/redis,yossigo/redis,PradheepShrinivasan/redis,flashbuckets/redis,izhoujie/redis,ncopa/redis,allengaller/redis,cusspvz/redis,brg-liuwei/redis,guker/redis,cusspvz/redis,badboy/redis,timothyohare/3rdPartySrc-redis,netroby/redis,seandsky/redis,shining-yang/redis,holstvoogd/redis,tjschuck/redis,PKRoma/redis,francischan714/redis,mattsta/redis,pedigree/redis,wujf/redis,xlzhan/redis,NBSW/redis,yossigo/redis,brg-liuwei/redis,yossigo/redis,wangyikai/redis,thomasdarimont/redis,StevenTsai/redis,dayuoba/redis,jackyan/redis,GrimDerp/redis,kensou97/redis,Wangyao14cyy/redis,hgl888/redis,janekmi/redis,ton31337/redis,guker/redis,Markgorden/redis,july2993/redis,wujf/redis,roth1002/redis,mingyaaaa/redis,tjschuck/redis,xlzhan/redis,roth1002/redis,dreamquster/redis,OmarQunsul/graph-redis,cloudrain21/redis,cnbin/redis,qiyang0221/redis,NBSW/redis,pmem/redis,SyntaxStacks/redis,zczhuohuo/redis,simplestbest/redis,j0hnma/szredis,YuanZhewei/redis,jackyan/redis,izhoujie/redis,tanghaodong25/redis,ofirluzon/redis,hawkchch/redis,itamarhaber/redis,pmem/redis,kaushik94/redis,soveran/redis,AALEKH/redis,iandyh/redis,pmem/redis,seppo0010/rlite-server,zguangyu/redis,pkdevbox/redis,Wangyao14cyy/redis,saisai/redis,netroby/redis,sunheehnus/redis,cloudrain21/redis,zhcy/redis,PradheepShrinivasan/redis,itamarhaber/redis,hawkchch/redis,gaoxianglong/redis,yuhc/redis-benchmark-enhanced,soloestoy/redis,roth1002/redis,j0hnma/szredis,programmecat/redis,fengshao0907/redis,j0hnma/szredis,simplestbest/redis,harrisonfeng/redis,kmiku7/redis,francischan714/redis,yossigo/redis,supasate/redis,francischan714/redis,MasahikoSawada/redis,janekmi/redis,huyuezheng/redis,RepmujNetsik/redis,pedigree/redis,rouzier/redis,holstvoogd/redis,cusspvz/redis,rogerlz/redis,seppo0010/redis,hornen/redis,GrimDerp/redis,abhiklodh/redis,Sciumo/redis,davidradunz/redis,elkingtonmcb/redis,ton31337/redis,CodeJuan/redis,ituncle/redis,soveran/redis,neomantra/redis,modulexcite/redis,GrimDerp/redis,blackmady/redis,ipmobiletech/redis,charsyam/redis,rogerchina/redis,hgl888/redis,kmiku7/redis,twskipper/redis,tjschuck/redis,xuguruogu/redis,cusspvz/redis,atreeyang/redis,linfangrong/redis,kensou97/redis,healerkx/redis,clamoriniere1A/redis,dayuoba/redis,dreamquster/redis,alenslan/redis,iandyh/redis,gaoxianglong/redis,Aliceljm1/redis,programmecat/redis,guker/redis,Wangyao14cyy/redis,holstvoogd/redis,4396/redis,iandyh/redis,flashbuckets/redis,mumingv/redis,citusdata/redis,vincent-vivian-liu/redis,ErikDubbelboer/redis,shreesundara/redis,pedigree/redis,pkdevbox/redis,mverrilli/redis,seppo0010/redis,xujunhai1991/redis,kaushik94/redis,xuguruogu/redis,itugs/redis,taoguan/redis,YuanZhewei/redis,yuhc/redis-benchmark-enhanced,hedisdb/hedis,mverrilli/redis,mcanthony/redis,zhcy/redis,jasonkying/redis,healerkx/redis,wbailey5/redis,h0x91b/redis,july2993/redis,ton31337/redis,wenxueliu/redis_comment,Aaron1992/redis,mverrilli/redis,colstrom/redis,vincent-vivian-liu/redis,nuxeh/redis,devaos/redis,190235047/redis,gilala/hbjredis,rogerchina/redis,antirez/redis,tellapart/redis,CodeJuan/redis,nuxeh/redis,spinlock/redis,spinlock/redis,twskipper/redis,aim-for-better/redis,Aaron1992/redis,gilala/hbjredis,ouyangkongtong/redis,abhiklodh/redis,GitHubMota/redis,wprice/redis,LongXQ/redis,ipmobiletech/redis,GrimDerp/redis,zhcy/redis,mumingv/redis,YuraLukashik/redis,OmarQunsul/graph-redis,xlzhan/redis,twskipper/redis,colstrom/redis,GitHubMota/redis,Soledad89/redis,mgk/redis,jasonkying/redis,pcarrier/redis,simplestbest/redis,yossigo/redis,guker/redis,seppo0010/rlite-server,StevenTsai/redis,clamoriniere1A/redis,healerkx/redis,zhiliaoniu/redis,wujf/redis,devaos/redis,iandyh/redis,ituncle/redis,h0x91b/redis,programmecat/redis,antirez/redis,modulexcite/redis,blackmady/redis,hgl888/redis,takeshineshiro/redis,csuhawk/redis,Aliceljm1/redis,Markgorden/redis,Aaron1992/redis,gilala/bjredis,zguangyu/redis,ipmobiletech/redis,hedisdb/hedis,valdsJohn/redis,healerkx/redis,seandsky/redis,oranagra/redis,190235047/redis,narma/redis,harrisonfeng/redis,ctripcorp/redis,abhiklodh/redis,mattsta/redis,soloestoy/redis,takeshineshiro/redis,zczhuohuo/redis,hawkchch/redis,YongMan/redis,ofirluzon/redis,huyuezheng/redis,saisai/redis,fengshao0907/redis,soveran/redis,valdsJohn/redis,huyuezheng/redis,mverrilli/redis,nnog/redis,atreeyang/redis,elkingtonmcb/redis,riyan8250/redis,jingjidejuren/redis,badboy/redis,kmiku7/redis,ipmobiletech/redis,CodeJuan/redis,arijitvt/redis,LongXQ/redis,josiahcarlson/redis,thomasdarimont/redis,mcanthony/redis,qiyang0221/redis,duanx/redis,NBSW/redis,xuguruogu/redis,Sciumo/redis,rogerlz/redis,allengaller/redis,weizijun/redis,soveran/redis,simplestbest/redis,zhcy/redis,oranagra/redis,linfangrong/redis,wangyikai/redis,xujunhai1991/redis,zhiliaoniu/redis,shining-yang/redis,tanghaodong25/redis,oranagra/redis,ytjiang/redis,NBSW/redis,rouzier/redis,soloestoy/redis,gilala/bjredis,itamarhaber/redis,zhiliaoniu/redis,kaushik94/redis,honestme/redis,huyuezheng/redis,jasonkying/redis,pedigree/redis,shining-yang/redis,janekmi/redis,hedisdb/hedis,cloudrain21/redis,davidradunz/redis,ytjiang/redis,4396/redis,gaoxianglong/redis,SyntaxStacks/redis,JoeWoo/redis,j0hnma/hszredis,tanghaodong25/redis,a-pavlov/redis,MasahikoSawada/redis